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Sulfur dioxide interaction with oxidized low-index iron surfaces
KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.ORCID iD: 0000-0003-0483-0602
KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.ORCID iD: 0000-0003-1631-4293
(English)Manuscript (preprint) (Other academic)
Abstract [en]

Sulfur dioxide was dosed on thin iron oxides grown on Fe(100) and Fe(110) (fromPaper 1 and Paper 2). It is found that the sulfur dioxide molecules adsorb as SO4-species at room temperature and that some of the adsorbed molecules dissociateupon adsorption and forming FeS2. The oxides corresponding to the lowest dosesof oxygen gas in Paper 1 and Paper 2 were annealed after the sulfur dioxide dos-ing, resulting in increased amount of dissociated molecules. The thicker oxides, onboth surfaces were exposed to another dose of sulfur dioxide, the change of sulfurcoverages show that the surfaces are almost saturated.

National Category
Physical Sciences
Identifiers
URN: urn:nbn:se:kth:diva-196126OAI: oai:DiVA.org:kth-196126DiVA: diva2:1046132
Note

QC 20161114

Available from: 2016-11-11 Created: 2016-11-11 Last updated: 2016-11-14Bibliographically approved
In thesis
1. Transition metal oxide surfaces: Surface structures and molecular interaction
Open this publication in new window or tab >>Transition metal oxide surfaces: Surface structures and molecular interaction
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Metal oxides are both corrosion products and useful materials with a wide range of applications. Two of the most used metals today are iron and copper. In this thesis, surface structures and molecular interaction with surfaces of iron oxides and copper oxides are studied using spectroscopy and microscopy methods.

 

The surface structures of iron oxides grown on the low-index iron (Fe) surfaces (100) and (110) have been studied during the initial oxidation phase. The oxidation condition for both iron surfaces was 400 °C and 1×10−6 mbar of oxygen gas. For the Fe(100)-surface, a Fe3O4(100)-film is formed beyond the oxygen adsorbate structures. For the Fe(110)-surface, a FeO(111)-film is first formed. When the FeO(111)-film grows thicker, it transforms into a Fe3O4(111)-film.

 

The surface structures of Cu2O(100) was studied and the main finding is that the most common surface structure that previously in literature has been described to have a periodicity of (3√2×√2)R45° actually has a periodicity described by the matrix (3,0;1,1). Furthermore, the low-binding energy component in the photoelectron spectroscopy O 1s-spectrum is determined to origin from surface oxygen atoms.

 

Sulfur dioxide, a corrosive molecule that in the environment to large share comes from human activities such as burning of fossil fuels, was studied using photoelectron spectroscopy when interacting with surfaces of iron oxide thin films and bulk Cu2O-surfaces. On the iron oxide thin film surfaces under ultra-high vacuum conditions, sulfur dioxide adsorbs partly as SO4-species and partly dissociates and forms FeS2. On the Cu2O-surfaces under ultra-high vacuum conditions, the adsorption of sulfur dioxide is non-dissociative and forms SO3-species. When interacting with near-ambient pressures of water, it is observed in the photoelectron spectroscopy S 2p-region that the sulfur from SO3-species shifts to Cu2S.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2016. 68 p.
Series
TRITA-ICT, 2016:36
National Category
Physical Sciences Physical Sciences
Research subject
Physics
Identifiers
urn:nbn:se:kth:diva-196130 (URN)978-91-7729-176-3 (ISBN)
Public defence
2016-12-16, Sal C, Kistagången 16, Kista, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 20161114

Available from: 2016-11-17 Created: 2016-11-11 Last updated: 2016-11-17Bibliographically approved

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